Modification of organosulfur compounds and water-soluble coal-derived material by anaerobic microorganisms

The transformation of organosulfur compounds by anaerobic microorganisms may be of interest for coal desulfurization. An anaerobic microbial community indigenous to cyanobacterial mats of a Yellowstone National Park hot spring was assessed for the ability to evolve volatile sulfur compounds from benzyl methyl sulfide, benzyl methyl disulfide, methionine and water-soluble lignite-derived material. The addition of methionine or benzyl methyl disulfide stimulated the production of methanethiol by slurries made with cyanobacterial mat material. Transformation of methionine appeared to be the direct result of microbial activity. However, the evolution of methanethiol from benzyl methyl disulfide appeared to be the indirect result of microbial activity, that is, the cleavage of the disulfide linkage may have resulted from the reduction by microbially produced hydrogen sulfide. Results indicated a transient interaction of hydrogen sulfide and methanethiol with the coal material. In separate studies, sulfate-reducing bacteria were examined for the modification of water-soluble lignite-derived material. As expected, the sulfur content of the soluble material increased under conditions of sulfate respiration. However, when grown fermentatively without the production of sulfide, two of the nine cultures examined reduced the sulfur content of the soluble material. Most of the cells in all the cultures immediately lysed upon the addition of the soluble material. By 2 weeks, cell densities were greater in cultures amended with soluble coal material than in control cultures.     

A comparative study of in vivo mutation assays: analysis of hprt, lacI, cII/cI and as mutational targets for N-nitroso-N-methylurea and benzo[a]pyrene in Big Blue mice

We have compared the response of the native hprt gene and the lacI, cII, and cI transgenes in Big Blue B6C3F1 mice following treatment with either N-nitroso-N-methylurea (MNU) or benzo[a]pyrene (BaP). Three weeks after mutagen treatment splenic T cells were isolated from the animals, and samples were either cultured to measure mutation at the native hprt locus or used to extract genomic DNA for transgene mutation analysis. Phage rescued from extracted DNA were plated in the presence of 5-bromo-4-chloro-3-indolyl-beta-d-galactopyranoside (X-gal) to score lacI mutations, or plated on a hflAB lawn to score cII and cI mutants. With MNU hprt mutant frequency increased in a dose-related, sublinear manner up to 78-fold above background at the highest dose tested (20 mg/kg). In comparison, the lacI transgene yielded only a 3.1-fold increase at this dose, and the cII and cI transgenes did not show any increase. With 150 mg/kg BaP a 5.8- and 8.7-fold increase in mutant frequency was observed at hprt and lacI, respectively, while only a 1.3-fold increase was observed at cII. DNA sequencing revealed an increase in GC-->TA transversions among the cII mutants, suggesting that the increase was related to BaP exposure. No significant increase in cI mutant frequency was observed. Therefore, the order of mutation assay sensitivity was hprt>lacI>cII/cI with MNU, and hprt approximately lacI> cII/cI with BaP. While the hflAB selection system offers significant advantages with respect to cost and effort when compared to the lacI assay, additional evaluation of its sensitivity is warranted.     

Long-term results of femorotibial bypass with vein or polytetrafluoroethylene

OBJECTIVE: The purpose of this study was to determine predictors of posttraumatic stress disorder (PTSD) in health care workers exposed to a disaster, in order to facilitate early case identification and prevention of subsequent morbidity. METHOD: Following an air disaster, 355 military medical health care workers were studied over an 18-month follow-up period. Measures included assessment of peritraumatic reactions associated with the disaster, the frequency of other stressful events after the disaster, and standard PTSD rating scales at 6, 12, and 18 months. RESULTS: Multivariate logistic regression of data on health care workers who cared for victims of the air disaster showed that PTSD was more likely to develop in those who had not completed college, those who had worked with burn victims, those who had experienced more stressful life events in a period of approximately 6 months following the disaster, and those who experienced emotional numbness immediately after the disaster. CONCLUSIONS: Results suggest that lower levels of education, exposure to grotesque burn injuries, stressful life events following exposure, and feelings of numbness following exposure are useful predictors of subsequent development of PTSD.     

The HMG-CoA reductase inhibitor atorvastatin increases the fractional clearance rate of postprandial triglyceride-rich lipoproteins in miniature pigs

We have previously shown in vivo that the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor atorvastatin decreases hepatic apolipoprotein B (apoB) secretion into plasma. To test the hypothesis that atorvastatin modulates exogenous triglyceride-rich lipoprotein (TRL) metabolism in vivo, an oral fat load (2 g fat/kg body wt) containing retinol (50 000 IU) was given to 6 control miniature pigs and to 6 animals after 28 days of treatment with atorvastatin 3 mg. kg-1. d-1. A multicompartmental model was developed by use of SAAM II and kinetic analysis performed on the plasma retinyl palmitate (RP) data. Peak TRL (d<1.006 g/mL; Sf>20) triglyceride concentrations were decreased 29% by atorvastatin, and the time to achieve this peak was delayed (5.2 versus 2.3 hours; P<0.01). The TRL triglyceride 0- to 12-hour area under the curve was decreased by 24%. In contrast, atorvastatin treatment had no effect on peak TRL RP concentrations, time to peak, or its rate of appearance into plasma; however, the TRL RP 0- to 12-hour area under the curve was decreased by 20%. Analysis of the RP kinetic parameters revealed that the TRL fractional clearance rate was increased significantly, 1.4-fold (3.093 versus 2.276 pools/h; P=0.012), with atorvastatin treatment. The percent conversion of TRL RP from the rapid-turnover to the slow-turnover compartment was decreased by 47% with atorvastatin treatment. The TRL RP fractional clearance rate was negatively correlated with very low density lipoprotein apoB production rate measured in the fasting state (r=-0.49). Thus, although atorvastatin had no effect on intestinal TRL assembly and secretion, plasma TRL clearance was significantly increased, an effect that may relate to a decreased competition for removal processes by hepatic very low density lipoprotein.     

An epidemic of Malassezia pachydermatis in an intensive care nursery associated with colonization of health care workers' pet dogs

BACKGROUND: Malassezia species are lipophilic yeasts that are emerging as nosocomial pathogens, particularly in low-birth-weight neonates who receive lipid emulsions. When a cluster of patients with Malassezia pachydermatis infection was identified in an intensive care nursery, we initiated an investigation. METHODS: A case patient was defined as any infant in the intensive care nursery who had a positive culture for M. pachydermatis between October 17, 1993, and January 18, 1995. We conducted a cohort study to identify risk factors for colonization and infection with M. pachydermatis. We collected cultures from the infants and the health care workers and from the health care workers' pets, since this organism has been associated with otitis externa in dogs. RESULTS: Fifteen infants met the case definition: eight with bloodstream infections, two with urinary tract infections, one with meningitis, and four with asymptomatic colonization. The case patients were significantly more likely than the other infants to weigh 1300 g or less (15 of 65 vs. 0 of 419, P<0.001). In a multivariate analysis of infants weighing 1300 g or less, the independent risk factors for colonization or infection with M. pachydermatis were a greater severity of concomitant illness (odds ratio, 19.7; P=0.001), arterial catheterization for nine or more days (odds ratio, 29.5; P=0.027), and exposure to Nurse A (odds ratio, 74.7; P=0.004). In a point-prevalence survey, 9 additional infants, 1 health care worker, and 12 of the health care workers' pet dogs had positive cultures for M. pachydermatis. The isolates from all 15 case patients, the 9 additional colonized infants, 1 health care worker, and 3 of the 12 dogs had identical patterns of restriction-fragment-length polymorphisms. CONCLUSIONS: In this outbreak, it is likely that M. pachydermatis was introduced into the intensive care nursery on health care workers' hands after being colonized from pet dogs at home. The organism persisted in the nursery through patient-to-patient transmission.     

Dynamic Systems and the Therapeutic Action of the Analyst: II. Clinical Application and Illustrations.

The author presents a dynamic systems approach to psychoanalytic practice. It depicts psychoanalysis as an activity-dependent, experientially based treatment in which the analyst's behavior toward a patient effects change in how the patient organizes and interprets self-experience and relates to others. The neurobiological and relational components of this approach are reviewed, and their implications for psychoanalytic process and technique are described. Several clinical vignettes illustrate the technical application, dynamic process, and therapeutic action of a dynamic systems perspective on psychoanalytic treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Results of microgravity investigation on adsorption and interfacial rheology of soluble surfactants from the experiment FAST onboard STS-107

Microgravity offers ideal diffusive conditions for the investigation of the dynamic processes involving surfactant adsorption. Here a summary of the results obtained during the FAST (Facility for Adsorption and Surface Tension studies) experiments on board the NASA Shuttle STS-107 is given. The measured data pertinent to interfacial rheology — i.e., the response of dynamic interfacial/surface tension to imposed perturbation of the interfacial area — for water-hexane and water-air interfaces, in the presence of different non-ionic surfactants are reported and utilised to test available models and to check fundamental aspects of the modelling of dilational rheology.     

Throw that epidemiologist out of the emergency room! Using the television series ER as a vehicle for teaching methodologists about medical issues

BACKGROUND: Epidemiology and biostatistics graduate students have diverse backgrounds, but many have little prior training in medicine or biology. This lack of content knowledge in future health researchers has recently been raised as a concern. METHODS: As part of a graduate course on the epidemiology of major diseases, the television series ER was used as a vehicle for learning more about diseases in general, and to become familiar with medical terminology and the ICD-10 by practicing coding on the patients seen. Furthermore, we wanted to provide human faces to the type of disease data students usually work with. RESULTS: In this article, the authors discuss how the ER sessions were organized and the problems that were encountered. The course evaluation concluded that the students found the exercise to be an interesting break from regular teaching.     

Lac repressor genetic map in real space

Here, we present a graphic display of the phenotypes of more than 4000 single amino acid substitution mutations on the three-dimensional structure of the lac repressor tetramer bound to DNA. The genetic data and the X-ray diffraction studies contribute to define an allosteric mechanism and yield a visual demonstration of the importance of core or buried residues in protein structure.